Due to the rapid increase of the quantity of personal computer used in the modern society, computer network is a good solution to the demand of resources sharing between different data terminal equipment(DTE). Local Area Network (LAN) is one type of network among many different computer networks. In general, LAN has different topologies which include bus topology, star topology and ring topology. A star topology of the network system is disclosed in FIG. 1 for reference.
A commercial network system known as ETHERNET is a system which meets the IEEE 802.3 standard in which working characteristics for a Carrier Sense, Multiple Access-Collision Detection (CSMA/CD) network are specified. The CSMA/CD network allows a plurality of nodes to interface with the network through its controller. The nodes may be any type of data terminal equipment for transmitting data to another DTE. The controller prepares data and control information or conditions incoming data and control signals according to the specified protocol. The data and control information prepared become data and control signals which are independent of the actual transmission medium used including coaxial cable and twisted pair (TP) wiring. The Medium Attachment Unit (MAU) functions to translate these medium independent signals into signal types specific to a particular medium. An attachment unit interface connects the controller and the MAU. The IEEE 802.3 Standard specifically defines the controller, the protocol between the attachment unit interface and the MAU, and the attachment unit interface characteristics as well. The MAU includes interfaces for twisted pair medium through TP ports and for coaxial cable medium through AUI ports.
A repeater may connect to a bus, to which multiple nodes are coupled, at one of its ports if it includes an AUI port (coaxial MAU). To meet timing requirement outlined in the IEEE 802.3 Standard, a network has a maximum of four repeater units in any series from one node to any other node. However, each single chip repeater circuit has only a limit number of ports available due to limitation of drive current. Therefore the number of available ports on a single monolithic repeater circuit significantly limits the growth of the network. This is specially true for the star topology since per single port of the repeater circuit connects only to one data terminal equipment.
Therefore, a repeater device implemented in monolithic silicon having port expansion capability was devised. For instance, the U.S. Pat. No. 5,265,123, hereby expressly incorporated by reference for all purpose, discloses an expandable repeater. Also disclosed in the mentioned U.S. Patent is one embodiment including two or more Integrated Multiport Repeater (IMR) combined with each other to function as a single repeater unit through the utilization of an arbiter function.